A typical conventional multi-rotor UAV is significantly less complex, easier to operate, less expensive, and easier to maintain than a typical conventional single rotor aerial vehicle, such as a helicopter or similar type aerial vehicle. For example, a conventional multi-rotor UAV may include four or more rotor motors, four or more propellers coupled thereto, four or more electronic speed controllers, a flight control system (auto pilot), an RC radio control, a frame, and a rechargeable battery, such as a lithium polymer (LiPo) or similar type rechargeable battery. In contrast, a single rotor aerial vehicle, such as a helicopter, may have thousands of parts. Additionally, single rotor aerial vehicles are also notoriously difficult to operate, diagnose problems, and are expensive to maintain.
Multi-rotor UAVs can perform vertical take-off and landing (VTOL) and are capable of aerial controls with similar maneuverability to single rotor aerial vehicles. Multi-rotor UAVs are relatively easy to assemble and may use commercial off the shelf (COTS) hardware including auto pilot flight controllers that are easily adaptable to standard configurations, e.g., a quad-rotor, a hex-rotor, an octo-rotor, and the like.
A typical conventional multi-rotor UAV relies solely on rechargeable battery or batteries to provide power to drive the rotor motors coupled to the propellers to provide flight. A typical conventional multi-rotor UAV includes a lithium polymer (LiPo) battery which may provide about 150 to 210 Wh/kg. This may provide a typical loaded flight time of about 15 minutes and an unloaded flight time of about 32 to 45 minutes. Advance lithium sulfur batteries may also be used which provide about 400 Wh/kg of power. In this case, the flight times are about 30 minutes in a loaded configuration.
In operation, the battery is used for the entire flight of the conventional multi-rotor UAV. Thus, when the battery is depleted, the UAV will stop operating. If the UAV is in flight, this can result in a catastrophic crashing of the UAV. Additionally, if aggressive maneuvers are needed during flight, such as quickly veering away from an object or moving quickly to avoid a potential threat, such maneuvers require instantaneous peak power which can quickly deplete the battery and significantly reduce flight time significantly.
Thus, conventional battery powered multi-rotor UAVs have limited endurance and payload and provide no backup power in the event the battery supply is depleted. Additionally, conventional commercial UAVs are very expensive and not commercially viable at scale today.
Conventional portable generators are heavy and may be difficult to transport to desired locations. Additionally, micro grid power systems used for electric grid power backup or ultra-micro power systems used in cell towers for power backup rely solely on batteries to provide the needed backup power.
Thus, there is a need for a small, lightweight, portable generator system which can provide power in such applications. Additionally, there is a need for UAVs with improved operational characteristics. For example, there is a need for UAVs capable of operating for longer durations.